A leaky feeder is an underground communications system used in underground mining and other tunnel environments. It consists of a coaxial cable run along tunnels which emits and receives radio waves, functioning as an extended antenna. The cable is “leaky” in that it has gaps or slots in its outer conductor to allow the radio signal to leak into or out of the cable along its entire length.

Because of this leakage of signal, line radios or amplifiers are required to be inserted at regular intervals, typically every 350 to 500 meters to boost the signal back up to transmission levels. The signal is usually picked up by portable radios carried by personnel. Transmissions from the transceivers are picked up by the feeder and carried to other parts of the tunnel, allowing two-way radio communication throughout the tunnel system.

One advantage of a leaky feeder cable is that you can lay it down as you excavate a mine. You can use splitters to send lengths of cable down different pathways. And since cable is flexible, there’s no problem moving the network around sharp corners and turns. You can even feed cable straight down a hole if need be.

Raveon’s M7 series is the preferred choice of radio for companies designing leaky feeder systems for real time transmission of critical data underground. Read More.